MRIs Help Fight High Risk of Breast Cancer

For women with a high risk of breast cancer because of genetic mutations or family history, yearly M.R.I. scans in addition to mammograms and breast exams may save lives, a new study finds.

The study, the first to measure survival in a large number of high-risk women receiving M.R.I.’s, found that after six years of follow-up, 93 percent of mutation carriers with cancer were still alive, compared with 74 percent alive at five years in earlier studies. In the new study, all of the women at high risk because of family history were still alive after six years.

Experts began several years ago to recommend yearly M.R.I. scans in addition to mammograms for high-risk women, because M.R.I. is better at finding tumors. Mammograms still detect some cancers that M.R.I.’s miss, so high-risk women are generally advised to have both tests. But until now, researchers did not know whether the combined testing saved lives.

“We have always assumed that if you find the cancer early, the patients will do better,” said Dr. Maxine Jochelson, director of imaging at the breast and imaging center at Memorial Sloan-Kettering Cancer Center in Manhattan (she was not involved in the study). “This is the first paper that really has taken a large number of women and shown that if you find disease earlier it does translate into some improved outcomes.”

The findings may offer a reprieve to some women with very high risk who thought that having their breasts removed preventively was the only way to avoid cancer and save their lives. More women may also become willing to be tested for mutations, since there could be a less drastic way to deal with them.

“Carefully screened with M.R.I., clinical breast examination and mammography, even women at high risk for the development of breast cancer may make a rational decision not to have prophylactic mastectomy as a risk-reducing intervention,” said Dr. Andrew D. Seidman, a breast cancer specialist at Memorial Sloan-Kettering who was not involved in the study.

But even careful screening may not protect as well as preventive surgery: four women in the study, all with BRCA mutations, died of breast cancer.

Breast M.R.I. is not recommended for most women, who have only an average risk of breast cancer, because the scans find too many possible abnormalities and lead to repeat scans and biopsies for things that turn out to be harmless. Even in this study of high-risk women, about 10 percent of the suspicious M.R.I. findings turned out to be false positives. The new study, published online in The Journal of Clinical Oncology, involved 2,157 high-risk women in the Netherlands. Some had mutations in genes called BRCA1 or BRCA2, which produce a lifetime breast cancer risk of 50 percent to 85 percent. Others had lifetime risks ranging from 15 percent to 50 percent based on family history. (An average woman’s lifetime risk is 12.2 percent.)

The research was directed by Dr. Jan G. M. Klijn, an emeritus professor of medical oncology at the Erasmus University in Rotterdam.

Dr. Klijn and Dr. Seidman said that it may be worth considering whether high-risk women should have M.R.I. twice a year. But the test is expensive — from $2,000 to more than $6,000.

A weakness in the study is that there was no control group. All the women had M.R.I.’s, so the researchers had to use a less reliable method, comparing their results with previous studies of women who did not have M.R.I.’s. Creating a control group would have been unethical, because the women were at high risk and there was reason to believe M.R.I. would help them.

A striking finding was that in women with a BRCA1 mutation, M.R.I. was far better than mammograms: M.R.I. found 66.7 percent of cancers in them, but mammograms found only 25 percent.

“The difference is stark, bigger than what I would have expected,” said Dr. Linda Moy, a specialist in breast imaging at New York University Langone Medical Center.

Dr. Moy said the new findings emphasized the need to monitor mutation carriers closely with M.R.I.